Referring to FIG. 1, U.S. Pat. No. 7,683,474 B2 (hereinafter referred to as the '474 patent) discloses a conventional light emitting diode (LED) device 30 that includes a metal heat sinking base 64, a walled container 32 disposed on the metal heat sinking base 64 and defining a surrounded volume, first and second conductors 40, 42 formed on the metal heat sinking base 64 within the surrounded volume of the walled container 32, a first pad 50 formed on the first conductor 40, a second pad 52 formed on the second conductor 42, at least one LED chip 44 disposed on the first pad 50, a wire 48 interconnecting the LED chip 44 and the second pad 52, and an encapsulant 54 filling the surrounded volume of the walled container 32.
The first conductor 40 and the second conductor 42 formed on the metal heat sinking base 64 are respectively electrically connected to the LED chip 44 through the first pad 50 and the second pad 52. Thus, electric power is supplied to the LED chip 44 through the first and second conductors 40, 42, and heat generated by operation of the LED chip 44 is also dissipated by the metal heat sinking base 64 through the first and second conductors 40, 42.
However, an adhesive layer (not shown) is required to be disposed between the first conductor 40 and the metal heat sinking base 64 so as to securely dispose the first conductor 40, which exerts a dual function in electric power transmission and heat dissipation, on the metal heat sinking base 64. Inclusion of the adhesive layer tends to decrease heat dissipating efficiency of the first conductor 40. Besides, due to the dual function of the first conductor 40, the first conductor 40 performs heat dissipation and electric power transmission at the same time, and heat dissipating efficiency of the first conductor 40 is unavoidably decreased and cannot be fully exploited. Therefore, there is plenty of room for improving the heat dissipating efficiency of the LED device.